When Lord Mandelson said Labour was “intensely relaxed about people getting
filthy rich” he may have been talking about himself.

His declarations on the House of Lords register of members’ interests give little clue as to how the 58-year-old career politician has made his fortune.

Neither his public speaking and writing firm Willbury, which collects proceeds from the sales of his memoirs, nor his consultancy firm Global Counsel have published accounts yet.

And the remuneration for his senior advisory role at Lazard investment bank has not been disclosed, although some reports have suggested it could be as much as £1 million a year. Under restrictions imposed on Lord Mandelson by Whitehall watchdogs, he was banned from lobbying ministers and civil servants after leaving government. But there are no restrictions on his work overseas.

He has developed close links with the rulers of oil-rich Kazakhstan and recently spoke at two events organised by the Kazakh investment company Samruk-Kazyna. He has also made shrewd property investments. In 1997 Lord Mandelson was living in a one-bedroom flat worth £250,000. Earlier this year, he and his partner, Reinaldo Avila da Silva, moved into an £8 million home in north London.